tory well deserving of our attention. Petrifactions throw much light on the natural history of the earth.

The first thing worthy of remark in petrifactions is their external form, which clearly shows that they have once belonged to the vegetable or the animal kingdom. The petrifaction of animals is not unfrequent. Aquatic animals are found petrified; and it is not uncommon to meet with entire fishes in this state, the least scales of which are distinctly visible; and the multitude of shells and worms found in the bowels of the earth, apparently converted into stone, is very great; and there are besides many petrifactions of animals found, no similar species of which are at present known to exist. The petrifactions of marine substances are found in great abundance in various parts of the earth; on the summits of the loftiest mountains, at an elevation of several thousand feet above the surface of the sea; and others at a great depth in the earth. Various species of petrified plants are also met with in different strata of the earth; and often the impressions which they have made are only seen, the substances themselves being destroyed. In some places whole trees are found buried more or less deep in the earth, and converted into a stony substance; but such petrifactions do not appear to be of a very ancient date.

It may with propriety be asked, how these petrified substances got into the earth, and particularly how they could be found on the highest mountains? And how animals, which generally live in the sea, and do not belong to our climate, have been transported so far from their natural abode? To explain this phenomenon many causes may be assigned. These petrifactions may be regarded as a certain proof that water once covered the greatest part of the earth; and as, wherever we dig, whether on the tops of the mountains, or in deepest mines in the earth, we find all kinds of marine productions, it would seem as if no more satisfactory explanation could be given. The great quantity of petrified shellfish found often in very high situations, and forming regular strata, gives us reason to believe that these heights once made a part of the bottom of the sea; and it is the more probable, because we know the bed of the ocean resembles the solid earth. We are yet very imperfectly acquainted with the manner in which nature effects these petrifactions. It is certain that bodies will not petrify in the open air, because animal and vegetable substances are dissolved or become putrid in that element; so that air must be wholly or partially excluded from the places where the process of petrifaction is going on. A dry soil has no petrifying property. Running waters may encrust some bodies, but cannot change them into stone; the very stream of the water would prevent it. A soft moist earth, containing calcareous matter in a state of solution, most probably contributes to petrifaction; the fluid penetrates into the pores of vegetable and animal substances, and as they dissolve deposits calcareous matter, which unites with, and adapts itself to, the substance in question. From the above account we may deduce some consequences which throw considerable light upon the subject. All animals and vegetables

are not equally proper to be converted into stone; for that purpose they should possess a certain hardness of texture, which would prevent their becoming putrid, before they became petrified. Petrifactions are chiefly formed in the interior of the earth, and the place where they are formed should be neither very wet nor very dry. All the kinds of stones which contain petrifactions, or form the substance of them, are the work of time, and are still daily producing. Such are the calcareous and argillaceous earths, and several others of a similar nature; and petrified bodies partake of the nature of these

stones.

Though petrifactions were of no other use than to throw some light upon the natural history of our globe, they would, on that account alone, highly merit our attention. But if we consider them as proofs of the secret operations and changes of nature, they will be very useful by manifesting the wonderful power and wisdom of God.

OCTOBER IX.

THE OPERATIONS OF NATURE ARE GRADUAL.

We may observe an admirable gradation, an insensible progress, from the simplest to the most complex perfection throughout nature; and there is no intermediate space which has not some characteristic of what precedes and of what follows; there is neither a void nor a break in the whole of nature.

Earthy particles form the chief composition of solid bodies, and are found in all substances decomposed by human art. From the union of earth with salts, oils, and sulphurs, &c. result different combinations of earths more or less compound, light, or compact. These insensibly lead us to the mineral kingdom. The different species of stones are very numerous, and their figure, colour, size, and hardness are very different. We find among them various metallic and saline matters, from which minerals and precious stones are produced. In the class of stones, some are fibrous, and have laminæ, or a sort of leaves, as slate, talc, litophytes, or stony marine plants, and the amianthus, or stony flower of mines; and these lead us from the mineral to the vegetable kingdom. The plant which seems to be the lowest in the scale of vegetation is the truffle, and next to it are the numerous species of mushrooms and mosses. All these plants are imperfect, and properly only constitute the limits of the vegetable kingdom. The most perfect plants naturally divide themselves into three great families, which are distributed over all the earth; these are herbs, trees, and shrubs.

The polypus seems to partake both of the vegetable and animal kingdom, and forms the connecting link between plants and animals. Worms commence the animal kingdom, and lead us to insects; those which are enclosed in a stony or scaly shell seem to unite

insects to shellfish. Between these, or rather next to them, is the class of reptiles, which by means of the water-snake are united to fish. The flying-fish leads us to birds. The ostrich, whose feet nearly resemble those of a goat, and which runs rather than flies, seems to link birds with quadrupeds. The ape appears to be between man and quadrupeds. There are gradations in human nature as in all other things; between the most perfect man and the ape the number of links is very great. And how many must there be between the most perfect man and the lowest angel! How many between the archangels and the Creator of all things! Here new links, new designs, new beauties and excellences, are perceptible; but in the spiritual world these gradations are concealed by an impenetrable veil, However, we have the consolation of understanding from Revelation, that the immense space between God and the cherubim is filled by Christ, who is God manifested in the flesh. By him human nature is glorified and exalted; by him man is elevated to the first rank of created beings, and is permitted even to approach the throne of the immortal God.

The little which we have said respecting these different links of nature suffices to show us that every thing in the universe is blended, that all holds together, and is united by the most intimate bonds. There is nothing without design, nothing which is not the immediate effect of some preceding cause, or which does not determine the existence of something that is to follow. Nature does not proceed by starts; every thing goes on gradually from the least to the most perfect, from the nearest to the most distant, from bodily perfection to mental excellence. But our knowledge of this immense chain of beings is still very imperfect; we are yet acquainted with very few of the links. However, defective as is our intelligence in this respect, it is ample enough to give us the most exalted ideas of that admirable series, and infinite diversity of beings, which compose the universe; and thus we are led to that Infinite Being, between whom and us the distance is immeasurable.

OCTOBER X.

FALL OF LEAVES.

The ravages which the approach of winter makes in the forests and in the gardens begin to be now perceived. All plants, with the exception of a very few, lose their most beautiful ornaments, the leaves. What is the cause of this change! The most natural seems to be the cold; for as soon as the first frost sets in, the leaves begin to fall, and the vegetables to lose their verdant hue. This is owing to the circulation of the sap being checked by the cold. But this is not the only cause of the fall of leaves, for it takes place in mild winters when there is no frost, and in those trees which are preserved from the

effects of the cold in greenhouses. Other causes are therefore instrumental in stripping the trees of their leaves. Perhaps they wither because their transpiration is not supplied by the necessary quantity of sap from the root, for it is certain that the branches increase in thickness after they have ceased to grow in length. When, therefore, at the time that the branches still daily grow, the stalks of the leaves do not increase, their fibres must necessarily be detached from the fibres of the branches, and consequently the leaves will then fall.

But we must not suppose that these fallen leaves are entirely lost, and no longer useful: both reason and experience inform us to the contrary. Nothing perishes, nothing is useless in the world, consequently the leaves which fall from trees and plants are of some use; they grow putrid, and become manure for the earth; snow and rain separate the saline particles from them, and convey them to the roots of trees; and when the leaves are thus strewed on the ground, they preserve the roots of young plants, form a shelter to seeds, and retain round them the necessary degree of heat and humidity. This is particularly remarkable in oak leaves: they furnish an excellent manure, not only to the tree itself, but also to the tender shoots; and they are particularly useful to pastures, by promoting the growth of the grass which they cover. These advantages are so important, that fallen leaves are never collected for the purpose of throwing them away, unless they are in such abundance, that the grass is rather choked up than nourished by them.

Leaves may serve as manure in various ways; they are laid in stables instead of straw, and thus make a very good litter for cattle; or they may be mixed with other kinds of manure. The mould they produce is particularly useful in gardens, where beds are made of it, which contribute much to the growth of fruits and young trees.

The fall of the leaf, in a moral point of view, may be considered as an emblem of human life, and the frailty of all earthly things. I am as a falling leaf; death walks by my side; perhaps to-day I shall wither, and to-morrow be converted into dust! My life hangs by a thread, and I may lose all my beauty and vigour in a single moment. But if I leave behind the well-matured fruits of love, righteousness, and holiness, I shall quit this world with honour, and joyfully prepare to meet my Creator and Judge!'

OCTOBER XI.

DIFFERENT SPECIES OF EARTHS.

We can only form conjectures respecting the interior of the earth. Those who labour in the mines have not been able to descend lower than nine hundred feet; for if they wished to penetrate deeper, the great pressure of the air would be fatal to them, even if they preserved themselves from the water, which increases in proportion to the

descent. But what is this depth in comparison of the semidiameter of the earth? The interior of the earth must then necessarily be in a great measure unknown to us; for miners themselves have scarcely penetrated through the first crust. All that we know is, that when

we have dug to the depth of some hundred feet, this crust is composed of different beds placed one above the other. These strata are much blended, and their direction, substance, thickness, and relative position, vary considerably in different places. Under common earth in gardens, clay and fat earth are generally found, and these are alternated by layers of sand, clay, and marl.

The division, then, of these different layers is quite arbitrary, and they may be more or less extended; but in comparing them together, that division seems to be most convenient which refers them, to seven classes.

First, black earth, which is composed of putrid animal and vegetable substances: it contains many salts and inflammable matters, and is properly dung. Second, clay, which is more compact than black earth, and retains water longer upon its surface. Third, sandy earth, which is hard, light, and dry, and neither retains water nor is dissolved in it. It is the poorest of all earths, though some plants will grow in it. Fourth, marl, which is softer, more mealy, and more readily attracts moisture. Fifth, bog, or marshy earth, which contains a vitriolic salt, too acid for plants. Sixth, chalk, which is dry, hard, and calcareous; yet some plants thrive in it. And, lastly, stony earth. The smoothest stones, however bare of earth, are yet covered with moss, which is a production of the vegetable kingdom; and birch will grow to a considerable height between stones, and in the clefts of rocks.

The different species of earths of which these strata are composed are disposed with much wisdom; for only to mention the principal advantages which result from them, these different layers of sand, of gravel, and of light earth, favour the passage of fresh water, which filters through them, becomes softer, and is afterwards distributed to supply the wants of man and animals. These strata also form the reservoirs and canals of springs and fountains. And it is remarkable, that these canals are found in every country upon the surface of the earth, and that they are composed of a light earth, which is sometimes mixed with a soil which is harder and more stony, and tends better to purify the water. The diversity of earth is also very useful to the vegetable kingdom; for it is owing to this that herbs, plants, and trees grow spontaneously in certain countries, whilst in others they require the assistance of art. All that art can effect in such cases is to imitate nature, which has prepared for the plants which grow of themselves the soil, the nutritive juices, and the degree of heat most favourable to vegetation. This variety of soils is the reason why some herbs and plants have their internal structure different from others of the same species. It often happens that some plants will thrive in the same soil in which others languish, and that the same fruits will taste differently in different countries. Plants whose